Return the Worker as documented from Supervised#prepare!

[tavianator]

Types of Changes

• Bug fix.

Contribution

• I added tests for my changes.
• I tested my changes locally.
• I agree to the Developer's Certificate of Origin 1.1.

[ioquatix]

It's not guaranteed that prepare! will return a worker. What problem are you trying to solve with this change?

[tavianator]

It's not guaranteed that prepare! will return a worker.

The docs say it returns the worker:

async-service-supervisor/lib/async/service/supervisor/supervised.rb

Lines 73 to 78 in 852c5a6

	# Create a supervised worker for the given instance.
	#
	# @parameter instance [Async::Container::Instance] The container instance.
	# @parameter state [Hash | Nil] Additional state to register with the supervisor.
	# @returns [Worker] The worker client.
	def prepare!(instance, state: nil)

Could change the docs instead.

What problem are you trying to solve with this change?

I don't think what I was doing when I ran into this was the right approach anyway, but I had overridden prepare! to start a recurring task to provide some metrics from the worker process and I wanted to get the utilization_registry from the worker, so I tried something like

def prepare!(instance)
  worker = super
  do_something_with(worker.utilization_registry)
  worker
end

[samuel-williams-shopify]

For now, I'll close this PR, as I'm not sure it solves the right problem. If you want to augment the worker, you'd be better off wrapping supervised_worker. Thanks for your effort and follow up.